To prevent dropping or irregular alignment of sheets from a pile by altering a set position in the same direction in a high speed range by altering a set position in a high speed range of a sheet release member by a controller, and automatically altering the set position by changing a thickness of the sheets.

Sheet delivery pawl members 7 for gripping and conveying a sheet 9 between right and left sheet-delivery chains 6 feeding in a direction C are supported at a predetermined interval. And, sheets released by the members 7 fed by a sheet-releasing mechanism 10 are loaded on a pile 8, and aligned at ends of the sheets on the way of dropping by a sheet contact 11. A sheet-release cam of the mechanism 10 is moved by movement of the chains 6, thereby opening/closing pawls of the members 7 to grip/release the sheet. When this controller 45 sets a position of the cam in a low speed range by low speed range input unit, it sets a function for deciding the position of the cam in a high speed range. When change of the low speed range to the high speed range is sensed by an encoder, sheet-releasing position of the cam is switched to setting in the high speed range.